1. Field of the Invention
This invention relates to methods and apparatus for heating food supported in closed containers by induction heating of conductive elements in the containers, and more particularly to apparatus for transporting and thermally conditioning a plurality of hot and cold food items for use in hospitals or the like.
2. Prior Art
A variety of thermally controlled transport systems are in use and have been proposed for moving individual food portions, packaged in containers from which they are to ultimately be consumed, and arranged with different similarly packaged foods on a tray to form an entire meal, from a central commissary in which the food is prepared to the ultimate consumers. These systems have reached their highest form of development in hospitals where patients must be served meals which vary on an individual basis. These transport systems have the objective of giving the central commissary a maximum degree of control over the composition of a meal and its thermal status to minimize the necessity for the use of highly skilled labor in the delivery of the meals to the patients. Since the patients may receive the meals a substantial time after they leave the kitchen or commissary it has been necessary to provide transport systems capable of refrigerating and heating the food during transport. Usually the food has previously been cooked and the heating is performed to thaw frozen portions or bring the food to a palatable serving temperature.
Historically, use of simple banquet covers over the food plates represented the first effort to maintain foods at proper temperatures during transport. To overcome the heat loss that inevitably resulted pellets of high thermal inertia were next proposed for incorporation into food containers and a pellet heating oven was established at the kitchen or central food assembly point. Pellet systems were superseded by transport carts having separate refrigerated and heated compartments but these carts required the assembly of the individual food containers into a complete meal when the cart reached the patient. The shortcomings of these systems, including the requirement for the exercise of skill in the final assembly of a meal for the patient and the time required for the assembly operation, led to the development of systems wherein the meal is fully assembled at a central point and individual resistance heaters, disposed in either the food containers or the transport trays are used to maintain food temperature during transport. These systems are expensive and their exposed parts create a danger of burning the handlers.
The present invention is directed toward a method and apparatus for heating food and a system for transporting food from a central location to the individual consumers which vests complete control over the organization of a meal and the serving temperature of the individual components of the meal in the central location, requiring only unskilled labor to deliver trays containing the prepared meals to the patients.